Draft gear



Api-i124. 192s.

W. H. COTTON DRAFT GEAR Filed Dec. 3; 1925 2 Sheets-Sheet 1 Aprilz4,192s.

W. H. COTTON DRAFTh GEAR Filed Dec.

2 Sheets-sheet 24 Patented Apr. 24, 192s.

' unir-Ea#STATES;

PATENT OFFICE.v

WALTERl H. COTTON, or CHICAGO, ILLINOIS, AssIGNORTO UNION DRAFT GEAR COM,-

, PANY,.OR CHICAGO, ILLINOIS, A CORPORATION OR DELAWARE.

DRAFT GEAR.

i Application lied December l 'Ifhe invention relates yto draft gearsof the friction type, applicablemore especially in freight service; and its Objects arc to secure lustrated in the accompanying drawings, inl

which v Y Fig. 1 is avcentral plan section ofthe gear,

portionsof the underframing of the car to which it is appl-iedbeing shown in plan ;v

'Figi'2 is a. centralv vertical longitudinal section of the gear, the coupler elements associatedtherewith being shown in elevation;

Fig. 3 is a view similar to Fig. 1, but the' sectional portion thereofbeing taken on thev line 3 3 of Fig. 2, and the shown under full com-pression;

Figs; ,4, 5 andY 6 are views inperspective ofk wedging elements and one of thel friction plates of the gear, the last figurebeing drawn to a reduced scale. Y

F orthe` purpose vof showing the manner gear being of applying the gear to a car, there are illustrated in the drawings conventional forms of center or draftsills at 10, a pair of draftlugs at 11, 11, a pair ofbuing lugs at 12,12, a coupler butt at 13, and a coupler extensionfor yoke at 14... These elements do not form any part ofthe invention, and may take any desired and suitable form.

The improvodgcar comprises a pair of chambered followers 15, 16, cooperating, respectively, with the draft and buliing lugs and being normally spaced apart; two groups, 17,v 18, of intercalating friction plates housed within the chambers ofthe followers; two sets of wedging elements, each housed within one of the followers, generally designated, respectively, fby the numerals 1'9, 20, interposed between the two groups of Vfriction plates,-there being associ'ated withfe'ach set of wedging elements springs for normally holding the members thereof in wedginggeng'agement; anda plurality of releasing springs which react between thetwo sets of friction plates ofeach groupthrough the medium of transverse releasing bars. The friction plates, as 21, are preferably vall? of like form, and are bifurcatedin order to provide space for the releasing springs, as 22, which are shown as four in number, vtwo being associated with each group O-f'plates.

a, 1923. yserial No. 678,094.

v The plates of the two sets of each group are longitudinally reversely arranged, and the releasing bars 23, .24, are located, respectively, at the inner ends of the plate slots, extend; entirely across the gear and form. seats for the releasing springs. The

cross members of the bifurcated or U-shaped friction plates constitute shoulders for en gagement by the releasing bars. lVhile it is desirable to form the plates VKas described, it is obvious that the physical unionof the upper and lower section of each nis not essential, it being necessary to the operation of the gear that each section be provided with a shoulder for cooperating with one of the releasing bars. Y

Each of the sets of'wedges 19, 20, comprises 'two-r elcments'25, 26', each having an outer fiat face for bearing against the inner platefof one of the groups of friction plates. The wedgingelemcnt 25 is seatedV against the cross member of the vadjaoent'follower, and is apertured to accommodate the releas-v ing bar atr that end ofthe gear, which is kat all times in engagement with the outer wall of this aperture by reason of the pressureof the releasingsprings. The wedging element 26 is not engaged by either follower. It is substantially of the same form as the element 25, but is bifurcated to provide clearance for the releasing bar. Y

Both of the elements 25, 26, are provided adjacent their forward kor thinner ends with instandinglugs 27, 2S, 29, 30, which project beyond the planes of the wedging faces, and each is channeled, as shown at 31, in line with each of its lugs to provide clearance for the lugs o f thecompanion elementv and chambers4 forl the reception of springs 32, 33, which react between aligned lugs ofthe twofelem'e'nts. Bythe action of these springs `the wedging faces ofthe two elements of each set `are normally maintained in contact andthe friction plates under compression. The inclination of the several wedging faces is considerably less than the angle of repose.

The length of the friction plates is such that when the gear is in release position their inner Or closed ends are spaced slightly from the inner face of the adjacent follower, as shown in Fig. 1, their opposite ends terminating at such distance from the other followerv that they do not make contact with its transverse wall when the gear is completely closed, as shown in Fig. 3.

In assembling the parts the two sets of friction plates are reversely disposed transversely of the gear. 'Ihc two sets are so arranged relatively that the inner plate of each group is in engagement with a wedging element 25 ofthe set which is secured within the follower with which that wedg- .ing element is associated, as shown in Ilig. As a result of this arrangement there is but very slight relative movement between the wedging elements 25 and the friction plates against which they bear, while there is a maximum of relative movement between these plates and the elements 26.

For convenience in assembling the gear set screws 34C may be run into the aperture, as 35, in thewedge element 26 until it presses the lug 27, of the element 25, inwardly. This action compresses the springs 32, 33, and hence lessens the width of the co-mbined wedge element and permits its easy insertion between the two groups of friction plates. After such insert-ion the set-screw may be re moved.

Upon the application of bufing stresses the follower 15 is moved lraclgwardly, carrying with it the adjacent wedging element 25 and the releasing bar 2li- Inasmuch as the friction plates are already under compression by reasoncf the action of the springs 32, 33, the adjacent wedging element 26 is frictionally held and the angle of the friction faces being quite acute a maximum of wedging effort is instantly developed. The advancing follower, coming at once into engagement with the rear' ends of the friction plates which are secured within it, carries these plates backwardly against the frictional resistance between them and the other set of plates.

The wedging elements at theopposite or inner end of the gear are immediately forced into more intimate relation by reason of the friction developed between the inner plate of the group 18 and the element 26 of 4that set, and thc compressive action upon the fric# tion plates `is substantially the same at both ends of the gear. A card diagramming the resistance of the gear would show a substantially instantaneous development of the maX- imum resistance, and this resistance remains constant until complete compression has occurred, for the reason that the friction between the wedge elements 26 and the plates with which they are engaged does not change after the initial augmentation of the wedging pressure. Upon the cessation of bufting stresses the gear is promptly released by the action of the springs 22, which are of sutlicient strength to instantly move outwardly the wedge element 25 at the forward end of the gear, through the bar 23, which, it will be observed, is, during the compressive action` out of engagement with the shoulders of the friction plates with which it cooperates. The two wedging elements are thus instantly separated sufliciently to reduce the compression upon the plates to the minimum. As soon as the retractive movement of the advance plates begins the wedging elcment 26 at the inner end of the gear is drawn forwardly by the frictional enga-gement therewith of the platehaving bearing upon it. The compression of the friction plates at the inner end of the gear is, therefore, similarly instantly reduced to the minimum, and the complete release of the gear is at once effected.

The acute angle of the wedging faces to the axis of the gear not only insures a desirable instantaneous development of maximum pressure upon the plates, but makes it possible to use wedging elements of small transverse dimension, and consequently occupying but very little space, thus leaving a large space at each side of these elements and permitting the use of a large number of friction plates without departing from the standard dimensions of the gear.

`The action of the gear under the influence of the stresses of draft is the same as in bulfing, though, of course, in the reverse direction.

It will be noted that while the springs, as 32, 33, normally urge the wedging elements with which they are associated into engagement, their action is vrelieved by relative movement ofy these elements incident to the compression ofthe gear. YThese springs become at once active as the gear is released and maintain the wedging elements in contact.

llVhile the construction shown and ldescribed is highly efficient, it may be departed from within the scope of the invention.

I claim as my invention- 1. In a draft gear, in combination a pair of opposed followers, frictional elemients relatively movable responsive tothe relative movement of the followers, two independent sets of compressing means relatively dis,- posed longitudinally of the gear for forcing the friction elements together with substantially uniform pressure throughoutl the .approaching movements of the followers, means againstwhich the compressing means react laterally, means for limiting the outward movement of the friction elements, and means for restoring the parts to normal positions upon release of the gear.

2. In a draft gear, in combination, two opposed chambered followers, two groups of intercalating friction plates enclosed within the followers, the plates lof each set of each group being endwise engageable by one of the followers. two sets of cooperating wedging elements interposed between the two groups of plates the members of each setfrictionally engaging the inner plate of each group, one set being enclosedfwithin each iso ` follower, one element of each set of wedging elements being positively acted upon by the enclosing follower the other element being floating, means for holding the elements of each set in wedging engagement, and means for restoring the parts to normal position after compression.

3. In a draft gear, in combination, two opposed chambered followers, two groups of intercalating friction plates enclosed within the followers, the plates of each set of each group being endwise engageable by one of the followers, two sets of Cooperating wedging elements interposed between the two groups of plates, one set enclosed within each follower, one element of each set of wedging elements being positively acted upon by the enclosing follower, the longitudinal positioning of the other wedging element of eachset being dependent mainly on its frictional engagement with one of the friction plates, spring means normally urging the wedging elements of Veach set together and means for restoring the parts to normal position after compression. l

4. In a draft gear, in combination, a

group of intercalating friction plates, twol independent sets of directly cooperating wedge elements applied one to each of the end portions of the plates, means for limiting the lateral outward movement of the plates, means against which the wedge sets react, means for advancing one of the wedges of either set on compression of the gear, and means for restoring the parts of` the gear to normal positions after compression. Y Y

5. In a draft gear, in combination, a pair of casings, two groups of intercalating friction plates housed within thecasings, two independentsets of wedge elements enclosed within the casings and interposed between the groups of plates, a spring reacting between the two elements of each set to urge them together, positive means for advancing or resisting the advance of one element of each set, the movement of the second element being resisted by friction and means for restoring the parts to normal positionafter compression. v

6. In a. draft gear, 1n combination, two

groups of intercalating friction plates, twoy `AIndependent sets of cooperating wedging elements interposed between the'groups, one

member of each set being adapted for positive engagement by a follower and the other member being floating, the members of the two setsbeing reversely arranged transversely of the gear, the parts being so arranged that each of the positively actuated wedging i elements engages a plate associated with the compression of the gear, apair of elements cooperating as wedges interposed between the frictionY elements and in frictional enagernent therewith, one of such elements eing positively associated with one of the followers, means for limiting outward movement of the friction elements, and means for restoring thev parts to normal positions on release of the gear. V

8. In a draft gear, in combination, a pair` of opposed chambered followers, two groups of intercalating friction plates, one set of the plates of each group being endwise engageable with the end portion of one of the followers, two independent sets of cooperating wedges interposed respectively between the end portionsof the groups of plates,

the back faces of the wedges frictionally engagingthe adjacent plate, springs normally urging the wedges of each plate into engagement, and releasing springs for restoring the gear parts to normal positions after compression of the gear.

WALTER H. COTTON. 

